There are two different use cases and we need support for both.
Personally I prefer flat rate for unlimited everything if we're talking cell phone. It's not like I'll cancel it from month to month.
But for $random_site that is linked to from HN... no way I'll pay for a subscription. But I wouldn't pay 0.25 either for one article. Give up on the whale pricing and charge 1 cent.
This use case also needs a frictionless way of paying. No way I'm making an account for each site.